An image captured by a digital camera provides some sense of the location of objects in a scene and the location of one object relative to another. Without information in a third dimension (depth), it can be difficult to make strict conclusions about locations and linear measurements.
A legacy stereo camera is a type of camera with two or more lenses with a separate image sensor for each lens. This allows the camera to simulate human binocular vision and the ability to capture three-dimensional (stereo) images. A legacy stereo camera has some ability to determine depth of objects in its field of view when the baseline, or distance, between the two cameras is known.
An array camera includes a plurality of individual imagers (i.e., cameras) that can capture images of a scene where the image obtained by each imager is from a slightly different viewpoint. The diversity of information between viewpoints can be used to calculate depth information. The depth calculations in an array camera are more sophisticated than in a stereo camera because additional combinations of images, from different cameras in the array, can be compared and correlated to make the estimates more robust in the presence of noise and aliasing. An array camera system typically still has reduced precision in determining depth beyond a certain distance from the camera because the information used to calculate depth becomes less diverse in magnitude the farther an object is from the camera.